Use of flunarizine for the topical treatment of glaucoma

ABSTRACT

Use of flunarizine, a calcium channel blocking agent known for use as cerebral and peripheral vasodilator, in the treatment of glaucoma by topical administration. Differently from other calcium channel blockers already tested for use as antiglaucoma agents, flunarizine is highly active in lowering the intraocular pressure when administered by the topical ophthalmic route. The invention also comprises anti-glaucoma preparations containing flunarizine, or combinations of flunarizine with beta-blockers such as timolol.

This Application is a 371 of PCT/IT98/00266, filed on Oct. 6, 1998.

SPECIFICATION

The present invention concerns the use of flunarizine for the topicaltreatment of glaucoma. More specifically, this invention relates to theuse of flunarizine, a calcium channel blocking agent known and employedas cerebral and peripheral vasodilator, in a new indication as anantiglaucoma agent for topical ophthalmic treatment.

As it is known, glaucoma is a pathological ophthalmic condition theunderlying causes of which are not well understood at present. Thiscondition is usually shown by a progressive increase of the intraocularpressure, leading to severe impairment of the eye structures, inparticular to damage to the optic nerve disc and to decrease in thevisual field, finally resulting in optic atrophy. The disease isgenerally connected to an insufficient outflow of aqueous humour fromthe eye, although other causes, such as, e.g., the production of aqueoushumour and the episcleral veins pressure, take part in the regulation ofthe intraocular pressure.

The rationale of the pharmacological therapy presently in use is tolower the intraocular pressure. The drugs currently used to that aim,divided into classes according to their mechanism of action, arebeta-blockers (such as timolol, betaxolol, levobunolol),sympathomimetics (such as epinephrine and dipivephrine),parasympathomimetics or miotics (such as pilocarpine and acetylcholine)and carbonic anhydrase inhibitors (such as acetazolamide anddichlorphenamide). Besides the foregoing drugs well established in use,the search for agents having less side effects and longer lastingactivity has lead to evaluate, more recently, the possibility of usingfor the treatment of glaucoma another class of drugs, i.e. the calciumblocking agents. The latter, also known as “calcium entry blockers” or“calcium antagonists”, are currently used as vasodilators and in thetreatment of cardiac affections. For such indications, the mostwidespread calcium antagonists are, e.g., nifedipine, diltiazem andverapamil.

The role of calcium in the dynamics of aqueous humour and in the controlof intraocular pressure has not yet been entirely clarified, although itis known that the production and the outflow of aqueous are modulatedalso by calcium. As concerns the formation of aqueous, it is to benoted, firstly, that the hydrostatic component due to the arterialpressure and to the pressure of the vessels feeding the ciliary body iscalcium-dependent, as it is confirmed by the known systemic vascularaction of calcium antagonists. Further, the osmotic pressure due toionic secretion at the level of the non-pigmented ciliary epithelium islikely to be modulated by calcium, as hypothesised by Abelson et al.(Abelson M. B., Gilbert C. M., Smith L. M., Sustained reduction ofintraocular pressure in humans with the calcium channel blockerverapamil, Am. J. Ophthamol. 105; 155 (1988)).

As far as the outflow of the aqueous humour is concerned, calcium ionsplay a direct role in modulating the pressure of episcleral veins, andsome studies suggest that calcium influences the outflow capacity, bymaintaining the structural integrity of the trabecuale and of theexterior wall of the Schlemm's canal.

In spite of the foregoing suggestions several experimental works, bothon animal models and clinical, and involving both systemic and topicaladministration, reported contradictory results about the activity ofcalcium channel blockers in the therapy of glaucoma. For instance,Monica et al. (Monica M. L., Hesse R. J., Messerli F. H., The effect ofa calcium-channel blocking agent on intraocular pressure, Am. J.Ophthalmol. 96, 814 (1983)) reports that the oral administration ofnitrendipine to patients with moderate hypertension but with normalintraocular pressure slightly lowered the latter, while Beatty andco-workers (Beatty J. F., Krupin T., Nichols P. F., Elevation ofintraocular pressure by calcium-channel blockers, Arch. Ophthalmol. 102;1072, (1984)) did not evidence any effect upon oral administration ofverapamil to rabbits, and did even report an increase in the intraocularpressure upon topical administration. More recently, for instance,Payene and coworkers (Payene, L. J., Slagle T. M., Cheeks L. T., Effectof calcium-channel blockers on intraocular pressure, Ophthalmic Res. 22;337, (1990)) obtained a reduction in the intraocular pressure uponsystemic administration of verapamil or nifedipine to rabbits, but didnot detect any significant effect upon topical administration of thesame agents or of diltiazem by the topical route.

In general, however, at least as far as verapamil is concerned, it maybe said that the administration of this drug to man normally results ina reduction of the intraocular pressure. A more consistent reductionupon topical administration has been explained, in particular, by a workof Ettl et al. (Ettl A., Daxer A., Hoffmann U., Calcium channel blockersin the management of low-tension and open-angle glaucoma, Am. J.Ophthalmol. 116; 778, (1993)). These authors have detected, in therabbit eye, verapamil levels 200 times higher than the levels obtainableby systemic administration.

Accordingly, the use of verapamil in the treatment of ocularhypertension is the object of the international PCT application No. WO92/07563, filed by Abelson (i.e., the first author cited above) et al. Alater publication in the name of the same author is the internationalapplication No. WO 96/03986, concerning the treatment of a particularform of glaucoma, referred to as low-tension glaucoma. This pathology ischaracterised by an intraocular pressure which is almost normal, inspite of the fact that all of the other symptoms of glaucoma arepresent. In the latter document the therapeutic proposal is genericallyextended to all calcium-antagonists, many representatives of which arementioned in a preliminary list. However, the only example of activeagent disclosed in the document and supported by experimental data isverapamil.

Another calcium blocking agent that was specifically proposed for use,in a patent document, in the treatment of intraocular hypertension isdiltiazem (French patent No. 2593395, published in 1987), while a listof more than one hundred calcium antagonists is presented in theinternational PCT application No. WO 93/23082. The latter concerns, foruse in the treatment of glaucoma, a combination of a compound whichlowers the intraocular pressure (i.e., a conventional antiglaucomaagent) and a calcium channel blocking agent. The disclosure does notcontain any specific example of preferred combination, nor anyexperimental detail regarding the activity of any combination.

Some experimental trials on verapamil also allowed to ascertain that theophthalmic use of the said agent causes an undesirable swelling of thecornea. (Green K., Cheeks L., Hull D. S., Effects of calcium channelblockers on rabbit corneal endothelial function, Curr. Eye Res. 13;401-408, (1994)). This is particularly critical if one considers the usefor the treatment of a chronic condition as is, actually, glaucoma.

Although the entire class of calcium antagonists has already beenconsidered for its potential use in the treatment of glaucoma, theredoes not seem to have been evidenced the particular activity, againstthis type of pathologies, of a specific agent belonging to the saidclass, i.e. flunarizine. It has now been found, and it is thesubject-matter of this invention, that the specific calcium antagonistflunarizine, when administered through the topical ocular route, is ableto lower the intraocular pressure in a surprisingly more marked way thanthe other calcium antagonists so far proposed and tested for the therapyof glaucoma.

Within the frame of the studies connected with this invention, it hasalso been found that some known receptors, referred to as a receptors,are localised in the ocular region, in particular in the ciliary bodyand in the iris, and that some specific “ligands”, having a σ-agonistactivity, significantly lower the ocular pressure. Since it has beenexperimentally found that flunarizine shows a σ-agonist activity whichis far higher than the activity of other calcium antagonists, thisproperty may explain the unexpectedly greater activity of flunarizine inlowering the intraocular pressure, if it is hypothesised that suchactivity is exerted according to mechanisms of action that are at leastpartially different from the other calcium blocking agents.

In order to identify the presence of a receptor sites in the eye thetechnique of “receptor binding” has been exploited. The latter has beencarried out on cell membranes obtained from the irido-ciliary bodycomplex. The irido-ciliary body complex had been explanted, aftersacrifice, from male albino rabbits of the New Zealand strain. Thetissue was homogenised in buffer and a fraction rich in cell membraneproteins was isolated, obtained by centrifugation. The concentration oftotal proteins has been evaluated by the method of Lowry (Lowry, J.Biol. Chem. 193; 265 (1951)). Aliquots of the said fraction of thehomogenate containing 300 μg of total proteins were incubated withscalar amounts of [³H](+)-pentazocine (which is used, for experimentalpurposes only, as a a ligand). The reaction was carried out at 37° C.for 150 minutes and then, after filtering, the radioactivity left on thefilters was measured by liquid scintillation. The apparent dissociationconstant (Kd) and the total number of receptors were determined, and itwas thus ascertained that [³H])(+)-pentazocine selectively binds toreceptor sites present in the iridociliary body region of the rabbit. Onthe basis of the present scientific knowledge, the said receptors appearto be of the type σ-1.

Further, “competitive binding” assays carried out with a constant isamount of [³H](+)-pentazocine and scalar amounts of(+)-N-allil-nor-meth-azocine (NANM) (which is used, for experimentalpurposes only, as a σ ligand), showed that the latter shift theradioactive ligands from the receptor sites. It has also been observed,by analysing the Hill coefficient, that NANM interacts with one onlyclass of a receptor sites.

In the frame of the same research it has been found that σ-agonistagents show an ocular anti-hypertensive activity. A 1% preparation ofNANM was administered (50 μl) in the conjunctival fornix of the righteye of male albino rabbits of the New Zealand strain, after measuringthe (baseline) intraocular pressure. Upon measuring again theintraocular pressure 60, 120, 180 e 240 minutes after the instillation,it has been ascertained that the intraocular pressure was significantlyreduced (p<0.01) 60 minutes after the instillation, in comparison withthe formulation containing the vehicle only.

Lastly, as it was pointed out before, studies of receptor bindingcarried out with flunarizine (some of which are presented in thefollowing) have shown that flunarizine has an affinity for σ-1 receptorswhich is not even comparable to the affinity shown by the other calciumchannel blocking agents tested.

Another advantageous aspect distinguishing flunarizine from the othercalcium channel blocking agents proposed so far for the topicaltreatment of glaucoma is, as it has now been found, that flunarizinedoes not show any side effect of corneal swelling.

Therefore, the present invention specifically provides the use offlunarizine, optionally in the form of a pharmaceutically acceptablesalt, for the topical treatment of glaucoma, i.e. the use offlunarizine, or of a pharmaceutically acceptable salt thereof, in themanufacture of a topical ophthalmic medicament for the treatment and/orthe prophylaxis of glaucoma. In general, the topical administration offlunarizine may take place by using a preparation in the form of anaqueous solution or suspension, or in the form a gel, an ointment or acream in a pharmaceutically acceptable ophthalmic vehicle, or in theform of an erodible ocular insert or of a “reservoir” system with apolymer membrane, to be placed in the conjunctival sac.

The concentration of flunarizine in an ophthalmic vehicle may range from10 μg/ml to 5 mg/ml, i.e. from 0.001 to 0.500% by weight. The optimalconcentration is chosen firstly on the basis of the dosage to beadministered: in the case of use in eye-drop form, for instance, onedrop should contain a sufficient amount of flunarizine for the drop tobe effective as such or when instilled twice (i.e., two drops). Othercriteria for the choice of the concentration are the ocular tolerability(it should be considered that the conjunctival sac, into which theophthalmic preparation is to be instilled, has a limited capacity) andthe stability of the active ingredient. The preferred concentration foran aqueous solution formulation (eye-drops) is 0.050% by weight, andpreferably the product is present in the form of the correspondinghydrochloride salt (optimal concentration of flunarizine hydrochloride:0.052%).

According to a particularly preferred embodiment of this invention, theanti-glaucoma activity of the proposed ophthalmic preparation is furtherenhanced by the presence, in combination with flunarizine, of aneffective amount of a beta-blocking agent. The class of beta-blockers(or β-adrenergic blockers), referred to in the foregoing, represents todate the most widespread class of anti-glaucoma agents. These agents areused in the topical treatment of chronic open angle glaucoma and, moregenerally, in the treatment of intraocular hypertension. Their mechanismof action mainly consists in reducing the production of the aqueoushumour, and therefore the unexpected enhanced activity of the proposedcombination of flunarizine (which has been found to be active inincreasing the outflow of aqueous) with a beta-blocker may reasonably beexplained in terms of a complementarity of the two actions.

Preferably, the concentration of beta-blocking agent in the combinationaccording to the invention is from 0.1 to 2.5% by weight, and mostpreferably said beta-blocking agent is timolol or a pharmaceuticallyacceptable salt thereof,

A vehicle that may be employed in an eye-drop preparation according tothe invention is the simple physiological saline solution containing0.9% by weight of sodium chloride. Such solution is isotonic withrespect to the tear fluid, and therefore it is well tolerated by theeye. However, also hypotonic solutions or suspensions may be employed,as it is known that these preparations are well tolerated by the oculartissues.

Other excipients may be added to the composition of the invention inorder to adjust the tonicity of the solutions or suspensions, so as tostabilise the active ingredient(s) and to increase the tolerability ofthe preparation. Specifically, any buffers should maintain the pH intothe range 4-8. For instance, the above saline solution may be bufferedwith any one of the buffers well known in the pharmaceutical art forophthalmic use, such as, e.g., phosphate buffer, or trizma buffer (i.e.,tri-hydroxymethyl amino methane), so as to obtain a physiological pH, inthe range of 7.0-7.4. Further, the solution may also have an osmolarityin the physiological range (295-305 mOsm/l). This allows to obtain abetter ocular tolerability, In addition, the formulation mayadvantageously contain an antioxidant, such as, e.g., gallates, ascorbicacid, superoxide dismutase (SOD), BHT, sodium metabisulphite,tocopherols, BHA, nordihydroguaiaretic acid, ascorbic acid esters,dimethylthiourea and the like.

The tolerability may be further enhanced by means of other excipientssuch as cyclodextrins, polysorbate 80 (or Tween 80), dextrane (e.g.,dextrane 70), polyethylene glycol (e.g. PEG 400), poloxamers and othersimilar agents. The formulation may include viscosifying/thickeningagents such as methylcellulose, polyvinyl alcohol, glucosamine glucans,polyvinyl pyrrolidone and the like, in order to increase the ocularbioavailability, the stability and the tolerability of the activeingredient(s).

The ocular bioavailability of flunarizine may be further enhanced by theaddition of substances which increase the corneal permeation of thedrug, such as, e.g., dimethyl sulphoxide, taurocholates, membranephospholipides, benzalkonium chloride and other surface active agentsfor ophthalmic use (such as disodium lauryl sulphosuccinate).

Lastly, in the preparations to be packaged in multidose bottlescompositions a preservative with antimicrobial activity will have to beadded, in order to prevent contamination of the product. Such agent maybe chosen among the preservative agents well known for this use in thepharmaceutical art.

Products to be administered in the form of suspensions should containsuitable agents such as carboxymethyl cellulose and the like. In theevent that the preparation is to be employed in the form of an ointment,a gel or a cream for ophthalmic use, flunarizine will be admixed withcarriers such as polyethylene glycols, polyacrylates, polyethyleneoxides, fatty acids and alcohols or lanolin, paraffin and other similarproducts. Suitable ingredients for the production of emulsions ormicroemulsions may be chosen among the following: diethyleneglycol-monobutyl ether, di(ethylene glycol) buthyl ether, caprylic acidethyl ester, oleic acid ethyl ester, soybean oil, hexadecane,tributyrin, ethylene glycol-monobutyl ether, 1-hexadecene, n-heptane,1-heptene, Tween 80, PEG, poloxamers, polyoxyethylene ethers.

The dosage of the main active ingredient of the invention, to beadministered by the topical route, may vary from about 20 μg to about200 μg per day for each eye. The prescription dosage of the ophthalmicpreparations based on flunarizine will depend on the daily dose thatwill be necessary to achieve the therapeutic effect and, obviously, onthe specific formulation employed. Ophthalmic solutions or suspensionswill require from 1 to 4 instiliations per day; ointments, gels andcreams will require 1 or 2 applications; solid inserts with polymericmatrix, either biodegradable or not, will require one onlyadministration per day.

The present invention further concerns compositions which allow theadministration of flunarizine through the topical ophthalmic route, andspecific ophthalmic compositions for use in the treatment and/or in theprophylaxis of glaucoma comprising, as an active ingredient, atherapeutically effective amount of flunarizine. A group of preferredcompositions have the following formulation (wherein all percentages areby weight):

flunarizine hydrochloride 0.059% (corresponding to 0.05% flunarizine)sodium chloride 0.10-0.80% trizma buffer 0.02-0.20% PEG 400 1.00-6.00%Tween 80 2.00-12.00% sodium metabisulphite 0.01-0.20% propyl gallate0.01-0.50% EDTA 0.005-0.20% purified water q.s. to 100%

optionally comprising further pharmaceutically acceptable ingredients.

In a particularly preferred embodiment of this invention, thecompositions for use in the treatment and/or in the prophylaxis ofglaucoma further contain from 0.1 to 2.5% by weight of a beta-blockingagent, the latter being by preference timolol or a pharmaceuticallyacceptable salt thereof, such as timolol maleate.

Some specific embodiments of the invention are described below formerely illustrative purposes, together with the results of theexperimental studies carried out on the proposed anti-glaucoma agent,including comparative tests with other calcium-blocking agents.

EXAMPLE 1 Ophthalmic Solution Based on Flunarizine

A composition according to the invention that turned out to beparticularly effective (the performance of which was experimentallyevaluated as it is partly reported further on) has the followingcomposition (the percentages being given by weight):

flunarizine hydrochloride 0.059% (corresponding to 0.050% flunarizine)sodium chloride 0.485% trizma buffer 0.100% PEG 400 2.500% Tween 805.000% sodium metabisulphite 0.050% propyl gallate 0.050% EDTA 0.010%purified water q.s. to 100%

The above composition is suitable for being packaged in single dosecontainers; in the event that a multidose packaging is desired, apreservative (such as, e.g., benzalkonium chloride) will have to beadded in order to maintain the sterility of the product for the wholeperiod of use.

EXAMPLE 2 Ophthalmic Microemulsion Based on Flunarizine

A composition suitable for use as an ophthalmic ointment was preparedaccording to the formulation given below (weight percentages):

flunarizine hydrochloride 0.059% (corresponding to 0.050% flunarizine)trizma buffer (to pH 7.20) 0.100% PEG 400 10.000% soybean oil 2.00%Tween 80 20.000% sodium metabisulphite 0.050% sorbitol 2.057% propylgallate 0.050% purified water q.s. to 100%

As a tonicity adjusting agent, 455 mg of sodium chloride per 100 ml(i.e. 0.455 wt. %) may be used in place of the above amount of sorbitol,

EXAMPLE 3 Ophthalmic Emulsion Based on Flunarizine

An ophthalmic product similar to that shown in the previous example, buthaving a coarser size of the drops of the dispersed phase, was obtainedexcluding the soybean oil from the composition, according to thefollowing formulation (weight percentages):

flunarizine hydrochloride 0.059% (corresponding to 0.050% flunarizine)trizma buffer (to pH 7.20) 0.100% PEG 400 2.000% Tween 80 7.000% sodiummetabisulphite 0.050% sorbitol 2.014% propyl gallate 0.050% purifiedwater q.s. to 100%

As an alternative to sorbitol as a tonicity adjusting agent, thecomposition may include 433 mg of sodium chloride per 100 ml (i.e. 0.433wt. %).

EXAMPLE 4 Ophthalmic Solution Based on a Combination of Flunarizine andTimolol

A particularly preferred composition according to the invention wasobtained by adding to the formulation of Example 1 a sufficient amountof imolol maleate to achieve a concentration of 0.5% by weight oftimolol in the verall composition (corresponding to about 0.68% byweight of timolol maleate). The concentrations of the other ingredientswere the same as specified above for Example 1.

Similarly, also the formulations given in Examples 2 and 3 can bemodified with the addition of a proper amount of timolol maleate. Alsoin this case, it is preferred to obtain a concentration of 0.5% byweight of timolol in the overall composition.

Experimental Results

An isotonic solution, buffered and viscosified according to theformulation of Example 1, but having variable concentrations offlunarizine (ranging from 0.01% to 0.1% by weight), was generallyreferred to as MEG 01 in the experimental work the results of which areset forth below. The experimentation also considered combinations offlunarizine and beta-blocking agents formulated as shown for timolol inExample 4. The combination of flunarizine and timolol was referred to asMEG 02. Some of the said experimental results are also shown in thegraphs of the accompanying drawings, wherein:

FIG. 1 shows the percent reduction in the intraocular pressure obtainedupon instillation of flunarizine in the eyes of rabbits withhypertension, in comparison with the corresponding reduction obtainedwith the instillation of placebo and with the instillation of othercalcium antagonists;

FIG. 2 shows the percent reduction in the intraocular pressure obtainedupon instillation, in the eyes of rabbits with ocular hypertension, offlunarizine at various concentrations; and

FIG. 3 shows the percent reduction in the intraocular pressure obtainedupon instillation, in the eyes of rabbits with ocular hypertension, offlunarizine in combination with various beta-blocking agents.

Pharmacodynamic Studies

a. Study on Rabbits with Normal Intraocular Pressure

The effects of the agent of the invention on the intraocular pressure ofrabbits showing normal baseline intraocular pressure were evaluated incomparison with the action of a placebo, and with that of various othercalcium channel blocking agents. Female pigmented rabbits of the ViennaBlue strain were used (supplied by Charles River Italiana, of Calco(CO)). The age of the animals at the time of starting theexperimentation was 9 weeks, and their weight was 2.0-2.5 kg.

The choice of a species with pigmented iris is due to the fact that thelatter represents a reliable model for the evaluation of possiblemodifications of the intraocular pressure caused by the products undertest. The strain chosen is genetically defined, so as to limit to aminimum the variability of the biological characteristics between oneanimal and the other.

The animals were kept in rooms maintained under constant and controlledconditions of temperature and humidity, illuminated for 12 hours a daywith artificial light and with continuous renovation of the air. Thefeed consisted of a standard diet having a constant and knowncomposition, and both feed and water were available ad libitum duringthe whole period of the test. The rabbits were stabled for 21 daysbefore starting the test, so as to allow a sufficient acclimatation andto suitably evaluate the health conditions of the rabbits. Eachexperimental group consisted of 4 animals, which were allotted to thetreatment groups in a randomised way.

Each different group of animals received, by instillation in the rightconjunctival fornix, 50 μl of the following products:

a) eyerops of MEG 01, containing 0.050 wt. % flunarizine (0.052 wt. %flunarizine hydrochloride);

b) placebo solution (i.e., the vehicle of MEG 01);

c) eye-drops containing 0.056 wt. % verapamil in the vehicle of MEG 01;

d) eye-drops containing 0.051 wt. % diltiazem in the vehicle of MEG 01;

e) eye-drops containing 0.043 wt. % nifedipine in the vehicle of MEG 01.

The weight concentrations of the various agents under test are chosen soas to correspond to the same molar concentration.

The pressure in the treated eye was measured by flattening tonometer(TonopenXL®, Mentor), 15 minutes before the instillation of the eyerops(time 0) and then 30, 60, 90, 120, 180 and 240 minutes after. As a localanaesthetic, 5 minutes before carrying out each measurement 25 μl of acommercial ophthalmic solution containing 0.4% oxybuprocainehydrochloride (Novesine®, Sandoz) was instilled. To carry out themeasurement the rabbits were placed in a suitably designed cage, thatprevents any sudden movement of the animal under test.

For each animal and at each of the times listed above the average ofthree subsequent measurements was calculated and recorded, each one saidmeasurements being made after 1 minute from the previous one. Theintraocular pressure values at the various times were compared with thevalues obtained before the treatment, by means of the Student's “t”test. The comparisons between different groups were made by processingthe data by the variance analysis (ANOVA) and, where possible, by theStudent's “t” test for the comparison of two different experimentalgroups. Values of p<0.05 were considered to be statisticallysignificant.

The following table shows the values of intraocular pressure determinedon each one of the animals treated, as well as the average values foreach test group (± standard deviation).

TABLE 1 Intraocular pressure in rabbits with normal pressure treatedwith the tested agents Intraocular pressure (mmHg) at the time (min)Rabbit No. Eye 0 30 60 90 120 180 240 Eye-drops with 0.050% flunarizine(MEG 01) 01 RE 17 15 14 15 15 15 17 02 RE 16 14 13 14 14 15 16 03 RE 1413 12 12 14 14 16 04 RE 16 12 12 14 14 14 16 average ± S.D. 15.7 ± 1.213.5 ± 1.3 12.7 ± 0.95 13.7 ± 1.2 14.2 ± 0.5 14.5 ± 0.5 16,2 ± 0,5Placebo 05 RE 15 16 16 15 15 16 16 06 RE 16 15 14 16 16 17 17 07 RE 1715 16 16 16 17 17 08 RE 15 15 16 16 18 15 17 average ± S.D. 15.7 ± 0.915.2 ± 0.5 15.5 ± 1.0 15.7 ± 0.5 15.7 ± 0.5 16.2 ± 0.9 16.7 ± 0.5Eye-drops with 0.056% verapamil 09 RE 17 16 15 15 16 16 17 10 RE 15 1414 13 13 16 15 11 RE 16 17 15 15 16 17 17 12 RE 16 15 15 15 16 16 17average ± S.D. 16 ± 0.8 15 ± 1.3 14.7 ± 0.5 14 ± 1.0 15.7 ± 0.5 16.2 ±0.5 16.5 ± 1.0 Eye-drops with 0.051% diltiazem 13 RE 15 14 14 14 15 1516 14 RE 16 15 14 14 15 16 16 15 RE 18 17 17 16 16 17 17 16 RE 18 15 1315 16 17 17 average ± S.D. 16.7 ± 1.5 15.2 ± 1.2 14.7 ± 0.9 14.7 ± 0.915 ± 0.5 16.2 ± 0.95 16 ± 0.6 Eye-drops with 0.043% nifedipine 17 RE 1615 14 16 16 17 17 18 RE 15 15 13 15 16 15 17 19 RE 14 13 13 15 16 15 1420 RE 18 16 15 16 16 17 18 average ± S.D. 15.7 ± 1.7 14.7 ± 1.2 13.7 ±0.9 15.5 ± 0.6 16.0 ± 1.5 16.5 ± 1.7 16 ± 0

As it is shown by the previous table, the MEG 01 eye-drops (containing0.050% flunarizine) produced a significant reduction in the intraocularpressure after one hour from the administration, while a productconsisting in the corresponding vehicle without flunarizine did notcause any significant modification in the intraocular pressure. In thelatter case, the pressure values measured upon administration of theeye-drops are not statistically different from the values recordedbefore the instillation (time 0: 15 minutes before the administration).

Furthermore, neither the verapamil formulation nor the diltiazemformulation, both using the same vehicle as MEG 01, did produce anyintraocular pressure decrease with respect to the placebo. Some minorreduction could be detected with the administration of nifedipine, butthis effect appears to be negligible in comparison with the responseobtained with MEG 01 containing 0.050 wt. % flunarizine.

Another series of tests was carried out on rabbits with normal base-lineintraocular pressure in order to compare the activity of flunarizinewith that of the proposed combination of flunarizine with abeta-blocking agent, and with the activity of a beta-blocking agentalone.

The following well-known beta-blockers were tested: timrolol (which is anon-selective beta-blocker, being active both on β₁ and on β₂ adrenergicreceptors), betaxolol (a cardioselective beta-blocker, active on the β₁adrenergic receptors only) and carteolol (which is not selective, but isendowed with an intrinsic sympathomimetic activity). The tests werecarried out according to the same experimental protocol described above,treating each different group of animals with the followingcompositions:

f) eye-drops of MEG 02, containing 0.050 wt. % flunarizine (0.052 wt. %flunarizine hydrochloride) in combination with 0.5 wt. % timolol (0.68wt. % timolol maleate);

g) eye-drops containing 0.050 wt. % flunarizine and 0.5 wt. % betaxololin the vehicle of MEG 02;

h) eye-drops containing 0.050 wt. % flunarizine and 2.0 wt. % carteololin the vehicle of MEG 02.

The results of this series of tests, obtained and processed in the sameway as those shown in Table 1, are presented in the following table. Inorder to make any comparison easier, the data obtained with flunarizinealone and with the placebo, i.e. with the groups of animals a) and b) ofthe previous experiment, are shown again in the following table.

TABLE 2 Intraocular pressure in rabbits with normal pressure treatedwith the tested agents Intraocular pressure (mmHg) at the time (min)Rabbit No. Eye 0 30 60 90 120 180 240 Eye-drops with 0.050% flunarizine(MEG 01) 01 RE 17 15 14 15 15 15 17 02 RE 16 14 13 14 14 15 16 03 RE 1413 12 12 14 14 16 04 RE 16 12 12 14 14 14 16 average ± S.D. 15.7 ± 1.213.5 ± 1.3 12.7 ± 0.95 13.7 ± 1.2 14.2 ± 0.5 14.5 ± 0.5 16,2 ± 0,5Placebo 05 RE 15 16 16 15 15 16 16 06 RE 16 15 14 16 16 17 17 07 RE 1715 16 16 16 17 17 08 RE 15 15 16 16 16 15 17 average ± S.D. 15.7 ± 0.915.2 ± 0.5 15.5 ± 1.0 15.7 ± 0.5 15.7 ± 0.5 16.2 ± 0.9 16.7 ± 0.5Eye-drops with 0.5% timolol 101 RE 16 15 14 14 15 16 16 102 RE 16 14 1314 15 16 17 103 RE 16 15 13 15 16 17 16 104 RE 15 15 14 15 16 15 15average ± S.D. 15.7 ± 0.5 14.7 ± 0.5 13.5 ± 0.6 14.5 ± 0.6 15.5 ± 0.616.0 ± 0.6 16.0 ± 0.8 Eye-drops with 0.050% flunarizine and 0.5% timolol(MEG 02) 105 RE 16 14 13 14 15 16 16 106 RE 17 13 14 14 14 15 17 107 RE16 14 12 14 15 16 16 108 RE 16 14 12 13 14 15 15 average ± S.D. 16.2 ±0.5 13.7 ± 0.5 12.7 ± 1.0 13.7 ± 0.5 14.5 ± 0.6 15.5 ± 0.6 16.2 ± 0.5Eye-drops with 0.050% flunarizine and 0.5% betaxolol 109 RE 15 14 14 1415 16 15 110 RE 16 14 14 14 16 16 17 111 RE 17 15 15 16 16 16 17 112 RE17 16 15 15 16 16 16 average ± S.D. 16.2 ± 1.0 14.7 ± 1.0 14.5 ± 0.614.7 ± 1.0 15.7 ± 0.5 16.0 ± 0 16.2 ± 1.0 Eye-drops with 0.050%flunarizine and 2.0% carteolol 113 RE 17 16 14 15 16 17 16 114 RE 16 1515 15 16 16 16 115 RE 16 13 14 15 16 16 17 116 RE 15 12 14 15 15 16 16average ± S.D. 16.0 ± 0.8 14.0 ± 1.8 14.2 ± 0.5 15.0 ± 0.0 15.7 ± 0.516.2 ± 0.5 16.2 ± 0.5

From the experimental results of the previous table it appears on onehand that, in the conditions of the test, flunarizine alone had a betterperformance in lowering the intraocular pressure than timolol alone. Onthe other hand, the data show that that the activity of flunarizine wasfurther enhanced by the addition of timolol in the formulation, as theperformance of the combination was better than that of flunarizinealone.

b. Study on Rabbits with Ocular Hypertension

Rabbits of the same type as those described in the previous section wereused for the following tests. The rabbits had been preliminarily treatedin the same way, and the stabling conditions were the same.

The experimental increase in the intraocular pressure was induced byadministration of σ- chymotrypsin. In the rabbit, the injection of thisenzyme in the posterior chamber causes, after one month from theadministration, an effect of ocular hypertension. This experimentalmodel is widely used, and has often been employed in order to evaluatethe activity of various antiglaucoma agents.

At the end of the quarantine period the rabbits were anaesthetised byintramuscular administration of ketamine hydrochloride and xylazinehydrochloride (RBI). The right eye was gently pushed outwardly afterinstilling 25 μl of Novesine® eye-drops, containing oxybuprocaine as ananaesthetic; then, a sterile solution of σ-chymotrypsin (SIGMA, Milan;150 units in 100 μl of physiologic sterile solution) was injected in theposterior chamber of the right eye by means of a 30G sterile needle.After the administration of the enzyme, the eye was thoroughly washedwith physiologic sterile solution in order to remove any traces ofα-chymotrypsin which could damage the ocular tissues. Then, 2 drops of acommercial ophthalmic antibiotic solution (Colbiocin®, SIFI S.p.A.,containing chloramphenicol, rolitetracycline, colistinmethanesulphonate) were instilled. The treatment was carried out 3 timesa day (at 8.00 a.m., 12.00 a.m. and 6.00 p.m.) for one week after theadministration of α-chymotrypsin. The rabbits were employed in the testsafter one month from the induction of ocular hypertension by means ofthe enzyme.

The rabbits, divided also in this case in groups of 4 animals, weretreated by instillation of 50 μl of the product under test in the rightconjunctival fornix. In a first experiment the agents employed were thesame as in the first test reported in the foregoing (MEG 01 eye-dropswith 0,050% flunarizine, placebo, and eye-drops with 0,056% verapamil,0,051% diltiazem and 0,043% nifedipine respectively).

The intraocular pressure in the treated eye was measured, according tothe same procedure as in the previous tests, 15 minutes before theinstillation of the eye-drops and 30, 60, 90, 120, 180 and 240 minutesafter. The values obtained were statistically analysed according to thecriteria mentioned in the foregoing.

The following table shows, for each test group, both the individualintraocular pressure responses and their average values (± standarddeviation). The average values of the intraocular pressure reduction,expressed in terms of percentage, are also diagrammatically translatedinto the graph of FIG. 1.

TABLE 3 Intraocular pressure in rabbits with normal pressure treatedwith the tested agents Intraocular pressure (mmHg) at the time (min)Rabbit No. Eye 0 30 60 90 120 180 240 Eye-drops with 0.050% flunarizine(MEG 01) 21 RE 57 47 45 50 51 56 56 22 RE 46 38 37 38 39 44 45 23 RE 3630 28 32 34 37 37 24 RE 52 43 41 43 45 51 51 average ± S.D. 47.7 ± 9.0339.5 ± 7.32  37.7 ± 7.25 40.7 ± 7.63 42.2 ± 7.36 47.0 ± 8.28 47.25 ±8.18  Placebo 25 RE 57 56 57 58 56 57 57 26 RE 47 48 46 47 48 48 47 27RE 41 42 43 42 41 42 43 28 RE 52 50 51 51 50 53 52 average ± S.D. 49.25± 6.84  49.0 ± 5.77 49.25 ± 6.13 49.5 ± 6.75 48.75 ± 6.18  50.0 ± 6.4849.7 ± 6.07 Eye-drops with 0.056% verapamil 29 RE 56 55 56 55 55 57 5630 RE 47 48 49 46 47 46 48 31 RE 42 40 43 41 41 42 43 32 RE 51 52 52 5051 50 51 average ± S.D. 49.0 ± 5.94 48.7 ± 6.5  50.0 ± 5.47 48.0 ± 5.9448.5 ± 5.97 48.75 ± 6.39  49.5 ± 5.44 Eye-drops with 0.051% diltiazem 33RE 55 55 53 54 56 56 55 34 RE 52 53 51 52 52 51 52 35 RE 47 48 46 46 4748 47 36 RE 42 42 40 41 43 43 41 average ± S.D. 49.0 ± 5.71 49.5 ± 5.8047.5 ± 5.80 48.2 ± 5.90 49.5 ± 5.68 49.0 ± 5.71 48.7 ± 6.13 Eye-dropswith 0.043% nifedipine 37 RE 54 55 53 52 53 54 54 38 RE 50 52 50 50 4948 49 39 RE 47 45 45 46 46 45 47 40 RE 41 39 39 38 40 41 42 average ±S.D. 48.0 ± 5.47 47.7 ± 7.18 46.75 ± 6.13 46.5 ± 6.19 47.0 ± 5.47 48.00± 4.98  48.00 ± 4.96

Table 3 shows that the administration of the vehicle alone does notresult in any significant variation in the intraocular pressure, whileMEG 01 with 0.050% flunarizine) caused a reduction in the intraocularpressure remarkably higher than that obtainable with the administrationof the other calcium antagonists tested. As it may be observed, thevalues of intraocular pressure in rabbits with ocular hypertension aftertreatment with ophthalmic solutions containing equivalent amounts ofverapamil, diltiazem or nifedipine, in the same vehicle as MEG 01, donot show any significant reduction.

In a second series of trials, employing identical procedure steps, theophthalmic solution according to the invention was tested at differentconcentrations of flunarzine, i.e. 0.1% and 0.01% by weight of activeingredient. The aim was to compare the response so obtained with theresponse observed with the MEG 01 eye-drops containing 0.05 wt. %flunarizine. The results are presented in the following table, and arealso illustrated (as average percent amounts of the intraocular pressurereduction detected) in the graph of FIG. 2.

TABLE 4 Intraocular pressure in rabbits with ocular hypertension treatedwith flunarizine Intraocular pressure (mmHg) at the time (min) RabbitNo. Eye 0 30 60 90 120 180 240 Eye-drops with 0.010% flunarizine 41 RE60 58 55 53 58 60 61 42 RE 65 61 59 60 62 64 65 43 RE 53 51 49 48 52 5252 44 RE 52 50 48 49 51 50 52 average ± S.D. 57.5 ± 6.13 55.0 ± 5.3552.7 ± 5.18 52.5 ± 5.44 55.7 ± 5.18 56.5 ± 6.60 57.5 ± 6.55 Eye-dropswith 0.050% flunarizine 21 RE 57 47 45 50 51 56 56 22 RE 46 38 37 38 3944 45 23 RE 36 30 28 32 34 37 37 24 RE 52 43 41 43 45 51 51 average ±S.D. 47.7 ± 9.03 39.5 ± 7.32 37.7 ± 7.27 40.7 ± 7.63 42.2 ± 7.36 47.0 ±8.28 47.2 ± 8.18 Eye-drops with 0.100% flunarizine 45 RE 58 48 45 49 5156 57 48 RE 48 40 38 41 43 47 49 47 RE 42 36 34 36 38 41 43 48 RE 51 4540 46 48 50 50 average ± S.D. 49.7 ± 6.6 42.2 ± 5.31 39.2 ± 4.57 43.0 ±5.71 45.0 ± 5.71 48.5 ± 6.24 49.7 ± 5.73

From the foregoing table it may be observed that the highest percentreduction in the intraocular pressure was shown by the MEG 01preparation with 0.05% flunarizine, while the preparation with thehighest concentration (0.1%) showed an activity comparable with that ofthe 0.05% preparation. This is shown more clearly in the graph of FIG.2.

In a further series of tests the activity of combinations of flunarizinewith a beta-blocking agent was tested on rabbits with hypertension. Theexperimental conditions were exactly the same as before. Three groups ofanimals were treated with the compositions defined under f), g) and h)in the previous section, and the results obtained are summarised in thefollowing table. Also in this case, the data already obtained in thesame experimental conditions for flunarizine alone and for the placeboare repeated for ease of comparison.

TABLE 5 Intraocular pressure in rabbits with ocular hypertension treatedwith the tested agents Intraocular pressure (mmHg) at the time (min)Rabbit No. Eye 0 30 60 90 120 180 240 Eye drops with 0.050% flunarizine(MEG 01) 21 RE 57 47 45 50 51 56 56 22 RE 46 38 37 38 39 44 45 23 RE 3630 28 32 34 37 37 24 RE 52 43 41 43 45 51 51 average ± S.D. 47.7 ± 9.039.5 ± 7.3 37.7 ± 7.2 40.7 ± 7.6 42.2 ± 7.4 47.0 ± 8.3 47.2 ± 8.2Placebo 25 RE 57 56 57 58 56 57 57 26 RE 47 48 46 47 48 48 47 27 RE 4141 43 42 41 42 43 28 RE 52 50 51 51 50 53 52 average ± S.D. 49.2 ± 6.849.0 ± 5.8 49.2 ± 6.1 49.5 ± 6.7 48.7 ± 6.2 50.0 ± 6.5 49.7 ± 6.1Eye-drops with 0.5% timolol 117 RE 53 43 42 42 46 52 53 118 RE 54 45 4242 45 48 51 119 RE 46 39 39 38 39 42 45 120 RE 43 40 36 37 40 42 44average ± S.D. 49.0 ± 5.3 41.7 ± 4.7 39.7 ± 2.9 39.7 ± 2.6 42.5 ± 3.546.0 ± 4.9 48.2 ± 4.4 Eye drops with 0.050% flunarizine and 0.5% timolol(MEG 02) 121 RE 52 35 33 33 36 38 41 122 RE 58 39 36 37 41 46 48 123 RE47 31 29 32 35 37 38 124 RE 45 32 26 30 36 36 35 average ± S.D. 50.5 ±5.8 34.2 ± 3.6 31.0 ± 4.4 33.0 ± 2.9 37.0 ± 2.7 39.2 ± 4.6 40.5 ± 5.6Eye-drops with 0.050% flunarizine and 0.5% betaxolol 125 RE 49 39 36 3842 42 43 126 RE 45 35 37 37 39 40 41 127 RE 56 44 42 46 47 49 49 128 RE55 45 41 43 47 46 51 average ± S.D. 51.2 ± 5.2 40.7 ± 4.6 39.0 ± 2.941.0 ± 4.2 43.7 ± 3.9 44.2 ± 4.0 46.0 ± 4.8 Eye-drops with 0.050%flunarizine and 2.0% carteoiol 129 RE 57 53 40 42 50 54 56 130 RE 52 4644 45 48 49 49 131 RE 47 37 39 40 44 43 43 132 RE 46 36 37 39 40 41 43average ± S.D. 50.5 ± 5.1 43.0 ± 8.0 40.0 ± 2.9 41.5 ± 2.6 45.5 ± 4.446.7 ± 5.9 47.7 ± 6.2

The data reported in Table 5, and even more clearly the diagram of FIG.3, evidence the remarkable activity of the combination of flunarizinewith timolol and, in general, the good performance of the combinationsof flunarizine with beta-blocking agents. Also in this case, flunarizinealone showed an effectiveness comparable to or better than that oftimolol alone.

Toxicity Studies

a. Evaluation of the Corneal Swelling

The evaluation of the thickness of the cornea was carried outecographically by means of a UBM System 840 (Humphrey Instruments, SanLeandro, Calif., USA). The apparatus includes a 50 MHz probe and allowsto visualise images on a display with a resolution of about 504 and avisualisation field of 5×5 mm. The software incorporated allows tomodify the focalisation depth of the ultrasound beam, and to capture theimage while varying its amplification.

The animals employed in this test were of the same type as thosedescribed in the foregoing, and were treated in the same way. The testwas carried out, after having anaesthetised the animal (with ketaminehydrochloride and xylazine hydrochloride), by placing into contact withthe eyeball tiny cups filled in with a coupling means (ultrasound gel).The rabbits received in the right eye a single instillation (50 μl) ofeach of the same agents employed in the pharmacodinamic studies: a) MEG01 eye-drops with 0.050% flunarizine, c) eye-drops containing 0.056 wt.% verapamil; d) eye-drops containing 0.051 wt. % diltiazem; d) eye-dropscontaining 0.043 wt. % nifedipine. In the left eye the rabbits receivedan instillation of an equal amount of placebo (vehicle of MEG 01 withoutany active ingredient).

The following table shows the corneal thickness as detected on variousgroups of 4 rabbits each, before the instillation and at fixed timeintervals after the instillation.

TABLE 6 Corneal thickness in rabbits topically treated with calciumantagonists Corneal thickness (mm) at the time (min) Rabbit No EyeBaseline 1 hour 2 hours 3 hours RE: MEG 01 with 0.050% flunarizine - LE:Placebo 49 RE 0.394 0.394 0.394 0.394 49 LE 0.394 0.394 0.394 0.394 50RE 0.347 0.347 0.347 0.347 50 LE 0.347 0.347 0.347 0.347 51 RE 0.3860.386 0.386 0.386 51 LE 0.386 0.386 0.386 0.386 52 RE 0.363 0.363 0.3630.363 52 LE 0.363 0.363 0.363 0.363 RE: eye-drops with 0.056%verapamil - LE: Placebo 53 RE 0.356 0.376 0.385 0.383 53 LE 0.356 0.3580.360 0.367 54 RE 0.384 0.398 0.406 0.402 54 LE 0.384 0.382 0.388 0.38055 RE 0.372 0.387 0.400 0.402 55 LE 0.372 0.374 0.368 0.372 58 RE 0.3920.401 0.494 0.410 56 LE 0.392 0.390 0.396 0.388 RE: eye-drops with0.051% diltiazem - LE: Placebo 57 RE 0.377 0.380 0.382 0.384 57 LE 0.3770.380 0.380 0.377 58 RE 0.389 0.392 0.394 0.396 58 LE 0.389 0.389 0.3250.387 59 RE 0.396 0.400 0.400 0.400 59 LE 0.396 0.396 0.394 0.398 60 RE0.358 0.362 0.364 0.364 60 LE 0.358 0.358 0.360 0.360 RE: eye-drops with0.043% nifedipine - LE: Placebo 61 RE 0.375 0.380 0.380 0.380 61 LE0.375 0.375 0.376 0.375 62 RE 0.372 0.380 0.378 0.378 62 LE 0.372 0.3740.372 0.372 63 RE 0.396 0.398 0.400 0.400 63 LE 0.396 0.396 0.396 0.39664 RE 0.384 0.388 0.389 0.390 64 LE 0.384 0.382 0.984 0.382

As it may be observed from the foregoing data, with the use of theproduct according to the invention no alteration has been detected inthe corneal thickness for the whole period of the test. On the contrary,the ophthalmic solution containing 0.056% verapamil caused comealswelling, with increases in thickness of about 15-20 μm/hour. Nosignificant effect has been noted for the eye-drops containing diltiazem(only slight swelling) or nifedipine.

b. Acute Tolerability

In order to evaluate the tolerability of the calcium channel blockingagent according to the invention when topically applied to the eye,rabbits (of the same kind as those employed in the previousexperimentation) were treated as follows, after an initial acclimatationperiod. On the first day, 12 instillations of MEG 01 (0.05%) in theright conjunctival fornix, of 0.05 ml each, were made at intervals of 30minutes. The contralateral eye was treated with placebo and served as acontrol.

The condition of the ocular tissues was observed according to the Draizemodified test (Spampinato S., Marino A., Bucolo C., Canossa M., BachettiT., Mangiafico S., Effect of sodium naproxen eye drops on rabbit ocularinflammation induced by sodium arachidonate, J. Ocular Pharm., 7 (2);125-133, (1991)). The examination was carried out every hour startingfrom the first administration for 7 hours, and then 24, 48 and 72 hoursafter the last treatment, giving arbitrary scores to the various aspectsof the palpebral and bulbar conjunctiva, of the iris and of the cornea.

No significant reddening of the conjunctiva was observed for the wholeperiod of the test, both in the eyes treated with MEG 01 eye-drops(0.05% wt. % flunarizine) and in the eyes treated with placebo. Nooedema was detected in any of the eyes tested. In addition, noalteration involving the iris was noted in any of the eyes treated, andthe presence of drain material was maintained at a normal level. Neitherany damage has been detected in the corneal tissues; two eyes onlyshowed a slight desepithelisation.

The results obtained show that the MEG 01 ophthalmic solution based on0.05% flunarizine is well tolerated in the rabbit eye after repeatedinstillation in the conjunctival fornix.

Binding Studies

The receptor binding technique was carried out on cell membranesobtained from the irido-ciliary body complex explanted, after sacrifice,from male albino rabbits of the New Zealand strain (Charles RiverItaliana, of Calco (CO)). The tissue was homogenised in buffer and theP₂, fraction, rich in cell membrane proteins, was isolated. The saidfraction was obtained by centrifugation according to what described inthe literature (Mach R. H., Smith C. R., Childers S. R. Ibogainepossesses a selective affinity for sigma 2 receptors, Life Sci. 57(4);5742). The La total protein concentration was determined with the Lowrymethod.

Aliquots of the P₂ fraction of the homogenate respectively containing300 μg of total proteins were incubated in polypropylene test tubescontaining scalar amounts of the calcium antagonists under test (i.e.flunarizine, verapamil, nifedipine and nimodipine), and a known amountof 3H(+)-N-allyl-nor-methazocine (SKF) (experimentally used as a aligand). The non specific binding was evaluated in presence ofhaloperidol.

All tests were carried out in duplicate. The reaction was maintained at37° C. for 150 minutes, followed by filtration on WhatmannGF/B filters.The radioactivity left on the filters was measured by liquidscintillation spectrometry. The IC₅₀ was determined, and the resultsobtained are shown in the following table.

TABLE 7 Effects of various calcium antagonists on the inhibition of³H(+)-N-allyl-nor-methazocine binding Substance IC₅₀ (nM) flunarizine23.9 verapamil >10,000 nifedipine >10,000 nimodipine >10,000 diltiazem>10,000

The preceding data confirm the findings of the research that lead to thepresent invention, which have been discussed in the introduction.Namely, the data show that flunarizine has an affinity on σ-1 receptors,as opposed to the other more known and studied calcium channel blockingagents, such as verapamil, nifedipine and diltiazem. This findingsuggests that the σ-1 receptors are involved in the mechanismresponsible of the intraocular pressure decrease caused by flunarizine,and that this particular feature is responsible of the surprisinglyhigher activity of flunarizine as an anti-glaucoma agent for topicaluse.

The present invention has been disclosed with particular reference tosome specific embodiments thereof, but it should be understood thatmodifications and changes may be made by the persons skilled in the artwithout departing from the scope of the invention as defined in theappended claims.

What is claimed is:
 1. Method for lowering ocular hypertension,comprising administering, to a patient in need thereof, a topicalophthalmic medicament containing flunarizine or a pharmaceuticallyacceptable salt thereof.
 2. Method according to claim 1, wherein saidtopical ophthalmic medicament is in the form of an aqueous solution orsuspension, or in the form a gel, an ointment or a cream in apharmaceutically acceptable ophthalmic vehicle, or in the form of anerodible ocular insert or of a “reservoir” system with a polymermembrane, to be placed in the conjunctival sac.
 3. Method according toclaim 1, wherein the flunarizine concentration in said ophthalmicmedicament is from 0.0001 to 0.500% by weight.
 4. Method according toclaim 1, wherein the flunarizine concentration is 0.050% by weight. 5.Method according to claim 1, wherein flunarizine is present in the saidophthalmic medicament in the form of its hydrochloride salt.
 6. Methodaccording to claim 1, wherein said topical ophthalmic medicament furthercontains a beta-blocking agent.
 7. Method according to claim 6, whereinthe concentration of beta-blocking agent in said ophthalmic medicamentis from 0.1 to 2.5% by weight.
 8. Method according to claim 6, whereinsaid beta-blocking agent is timolol or a pharmaceutically acceptablesalt thereof.
 9. Method according to claim 1, wherein said topicalophthalmic medicament is in the form of an aqueous solution and furthercontains one or more tonicity adjusting agents, one or more buffers andone or more antioxidants.
 10. Method according to claim 1, wherein saidtopical ophthalmic medicament further contains one or more agentsimproving the ocular tolerability chosen from cyclodextrins, polysorbate80 (or Tween 80), dextrane, polyethylene glycol and poloxamers. 11.Method according to claim 1, wherein said topical ophthalmic medicamentfurther contains one or more preservatives or antimicrobial agents.